Handling a really old rusty acetylene tank.

[RJSakowski]

Can you elaborate on this? I am unfamiliar. If there is a small amount of acetylene in the tank what will happen if you vent it? What causes self ignition? 15 PSI is room air?

That's 15 psi gauge ir 30 psi absolute. There will be no problem cracking the valve. Vent is slowly and in open air in absence of any ignition source. Allow plenty of time for any acetylene to vent completely before any further action. Acetylene tanks are filled with a diatomaceous earth saturated with acetone. The acetylene dissolves in the acetone. Once the tank is completely purged, the fitting can be unscrewed and the contents removed.

If you are uncomfortable with any of this, take the tank to a professional for disposal.

BTW, I have one of these to process myself although mine hasn't been sitting outside.

 

[rwm]

Thanks RJ. I have one also.
I read that acetylene is unstable even without oxygen and can "violently decompose." I really don't understand this. Surely at the top of any tank there is un-dissolved C2H2 at whatever PSI is left in the tank. Wouldn't this pose a problem?

 

[savarin]

acetylene needs pretty high temps to violently decompose. I dont think you have any cause to worry about that tank.
The worse case I've personally seen was the sparks fro a large angle grinder falling at the base of a cylinder that had a very tiny leak in the bottom plug. That caught fire and I ran for it.. The boss tipped the cylinder over and an extinguisher put it out.

 

[Gnpenning]

Wondering why no pictures?? Everyone's level of rusty is different. Just check the car world and different parts of the country. I believe you that it's rusty, but is it surface rust or deep pitted rust. Huge difference in how it should/could be handled. Ymmv

 

[Bi11Hudson]

Acetylene is a "nasty" gas put off by calcium carbide getting wet. The tank can be transported horizontally but must stand upright for an hour (give or take) before opening the valve. As noted above, the inside is filled with an absorbant solid and acetone. The gas then mixes with that under pressure. I have had an acetylene tank catch fire (~sparks?) on the hose side of the regulator. It was wheeled off to an isolated area and allowed to burn off. The regulator was scrapped, it wasn't burned but a JIC (just in case) case. When the flames first appeared, we all "headed for the hills". When it showed no increase in flame was when the carriage was wheeled out. Acetylene has been declining in "popularity" in recent years, superceded by "less dangerous" fuel gasses. In 1990, cutting steel was done with natural gas. (methane?) Acetylene is reserved for use where the higher flame temperature is required.

A tank that old could be an expended tank that was "lost" in the weeds so someone didn't need to deal with it. That happens regularly with remote location work crews. Tanks in use, partially filled, are usually transported in a cage, some form of cradle and chained in so they don't tip over. To be "lost" is possibly indicative of an expended tank.

Make a "sound" judgement of the condition of the tank, if it has surface rust or deep pitting. In case of the former, stand it upright to transport, if possible. If the latter, vent the valve to open air and walk away for a day or two. Assuming it resides in "open air", don't try near any building or activity. Just crack open enough to bleed it off in a few hours. . . As noted above, if you can hear the hissing, it's open too much.

The important thing to keep in mind is that even with the gas gone, there is still likely some acetone (flammable) inside. The optimum solution is to pass things along to the local fire department, letting them deal with it. They'll make a big foo-fah-rah out of the whole deal. For show likely and for training of younger crews. Once bled off, the tank can be salvaged but really isn't worth the effort to dispose of the acetone and filler material. "Maybe it will be worth a chuckle to ask for my deposit back." would be an option. Just be ready for the questions.

.

 

[Reddinr]

A tank that old could be an expended tank that was "lost" in the weeds

That is likely. It is near my well-house, found only recently because I cleared a bunch of over-growth. I think it was probably used up when they welded the well-pipe sections together and then it was lost in the shuffle.

It sounds like my local Linde (Praxair) dealer will take it. They said "we can probably take it". Problem solved, I think.

[EDIT]
BTW, I'm not sure what was in the tank. The paper label is completely faded the tank color was green but I understand that doesn't always mean anything.

Photo:

 

[francist]

Nice picture! Seriously, it is nice picture… reminds me of some ancient monolith in the jungles of Thailand or something.

-frank

 

[pontiac428]

That's a high-pressure gas, probably oxygen or argon depending on the valve. I bet after de-rusting and hydrostatic testing, the bottle will still be serviceable.

 

[Reddinr]

You're right John. I used an image editing program and was able to boost the contrast on the label pic. so I could read it. It was oxygen. The tank cap is on there tight. Because it is/was oxygen I didn't want to put a bunch of oil on it to free it up. I'm going to take it back as-is.

Thanks Frank. I'm working on photography as a hobby. Yet another hobby. Yet another hobby I don't have quite enough time for! When I took it I was thinking "2001 A Space Odyssey". It looks like it grew out of the ground right there.